I Have A Psychotherapy Client Who Is A Breast Cancer

I have a psychotherapy client who is a breast cancer survivor. She is about age 50. She had chemotherapy treatment about 6 years ago and was on Tamoxifen for 5 years, discontinued about 6 months ago, because her oncologist felt it was causing her mood disorder symptoms. In my clinical opinion, she currently has all the symptoms of borderline personality disorder, with the exception of self-harm or suicidal ideation and no reckless or impulsive behaviors. She came to me treated for both depression and anxiety with several medications (anti-depressant, mood stabilizer and benzodiazepene). She did not have any of these personality or mood disorder symptoms prior to her cancer treatment. Is it possibly permanent changes due to the treatment and if so, what form of therapy can be most effective for her?